The invention relates to a molding apparatus, particularly a corrugator for the manufacture of pipes, preferably corrugated pipes, with at least two series of circulating mold jaw parts or mold blocks, which preferably have a same molding shape. The circulating mold jaw parts form a molding channel in an assigned area and the series are guided in respective rotating guides. The molding apparatus has at least one exchange member along at least one of the circulation and/or pass round guides of at least one of the mold jaw series, wherein at least one alternating mold jaw is provided that has an optional profile or that has another molding design of the pipe.
Corrugators for the manufacture of corrugated pipes are well known in the state of the art. As long as corrugated pipes are to be manufactured with a constant shape in a longitudinal direction it is possible to use conventional infinite corrugators with circulating mold jaw parts without encountering any problems. However, if corrugated pipes are to be manufactured having certain optional profile sections, it is necessary that these optional profiles be fitted into a mold jaw part chain, such as mold jaw parts or mold blocks for sleeves for example. Problems arise from the fact that these optional designs of corrugated pipes or pipes in general can only be provided on a same and hence rigidly assigned place. A variable optional design in the course of a continuously produced corrugated pipe without an interruption of the production process in the corrugator is not possible. The usual procedure is to include optional designs at certain positions in the corrugated pipe, which needs to be done at regular intervals or sections. This regularity is a result of the specific length of a certain mold jaw part chain. This means, that if an optional profile is required, every third length of a mold jaw part chain, it appears three times in each respective section of the corrugated pipe but two of these optional profiles are unused. These unused optional profiles can cause problems since they can become weak points.
The prior art describes an experiment in U.S. Pat. No. 4,325,685 A1 for a vertically aligned corrugator in which certain flexibility is created by providing mold jaw parts with multiple profiles. Among those multiple profiles are also optional profiles. These types of very wide mold jaw parts can be shifted horizontally on a vertically aligned machine table via a switch arrangement, so that an optional profile can be inserted when required. This solution, however, requires that if a certain flexibility is desired, each mold jaw part in a mold jaw part series needs to be designed accordingly complex having multiple profiles as well as optional profiles. As a result, a corrugator of this known type is extremely complicated, expensive, and in addition to that also delicate. Furthermore, the lateral positioning causes a problem in that the mold jaw parts can not be exactly aligned to the molding channel such that irregularities within the pipe profile arise.
EP 0 048 113 A2 and U.S. Pat. No. 3,981,663 also show modifications of corrugators which are also not able to solve, the aforementioned problems.
It is therefore an object of the present invention to provide a molding apparatus, particularly a corrugator, which can be flexibly used for the production of pipes and preferably corrugated pipes having an acceptable investment expenditure, and which can be flexibly provided with optional profiles.
The aforementioned object is partially or completely achieved in accordance with the invention by means of a molding apparatus having at least an exchange member along at least one of the circulation and/or pass round guides of at least one of the mold jaw series, wherein at least an alternating mold jaw is provided that has an optional profile or that has another molding design of the pipe.
It is evident that mold jaw parts or alternating mold jaw parts are used, which can provide more than one type of corrugated pipes or corrugated pipes with more than one diameter. The other types of corrugated pipes or corrugated pipes with different diameters can be used by adjustment of a machine table with respect to a nozzle of an extruder, from which the soft-plastic moldable plastic tube for the production of pipes or corrugated pipes comes out. For this it is necessary to interrupt the production process. Naturally, the extrusion nozzle can also be adjusted, or extrusion nozzle switches or extension pieces can be used in order to bring other mold jaw parts into action for the production of other types of corrugated pipes or corrugated pipes with different diameters.
Only a small number of mold jaw parts is replaced during a mold jaw part exchange, which occurs in accordance with the invention at a respective exchange member.
Advantageously, at least one exchange member is provided along each of the mold jaw part series. If required, two or more exchange members are provided along a mold jaw part series or a circulation and/or pass round guide.
The exchange member has at least two chambers, and each of the chambers has an entrance and an exit. The chambers are at least approximately similarly shaped as the circulation and/or pass round guides. This way, at least one of the chambers can be used as part of a pass round guide, so that it can serve as a guide for the mold jaw part series through the exchange member or the respective chamber of the exchange member. The respective chamber which is not used as a circulation and/or pass round guide serves as a reservoir for exchanging mold jaw parts, this means mold jaw parts with optional profiles, or for mold jaw parts that have been replaced with exchangeable mold jaw parts.
Of course, a respective exchange member can also be provided with three or more chambers, which are either included or excluded into the pass round guide, as desired, in order to include other mold jaw parts or exchangeable mold jaw parts with optional profiles, markings or the likes into the mold jaw part series that is used at a certain time.
At least one of the chambers of the exchange member has at least one exchangeable mold jaw part. Of course, a respective chamber can have multiple exchangeable mold jaw parts as per desired profile of a particular pipe product or corrugated pipe product.
The exchange member can be adjusted manually but it is advantageous to provide a drive section to remove a chamber with at least one mold jaw part from the pass round and/or circulation guide and to insert another chamber with at least one exchangeable mold jaw part, for example with an optional profile, into the circulation guide.
In accordance with the invention it is possible that the number of mold jaw parts in a mold jaw part series is smaller than the maximum number of mold jaw parts in a circulation guide. This requires a conveyor in order to move the mold jaw parts outside the molding channel faster than in the molding channel. This makes it possible to use less mold jaw parts in the corrugator than would be necessary for a closed mold jaw part series or a mold jaw part chain. This can be achieved for example by advance threads having different leads.
The changing of mold jaw parts is not so difficult in large corrugators because the low speed of circulation or passing round provides enough time to remove one mold jaw part and to replace it with another one.
Advantageously, the exchange member or exchange members are arranged in the area of the circulation guides where the molding channel is open. In other words, the mold jaw parts are not closed in the area in which the exchange member or exchange members are arranged, which means closed out of gear with the pipe. It is particularly advantageous to place the exchange members in the linear region of the return side of the molding channel of the apparatus or corrugators in accordance with the invention.
The drive section of the exchange member has preferably a cross slider that inserts one of the chambers into the pass round guides or that removes the other chamber which is presently in the circulation guides. The cross slider is preferably designed to carry out a linear motion. This linear motion proceeds particularly in the plane of the circulation guides or in the plane of the machine table of the respective circulation guides.
The drive section can work electro-mechanically, electro-magnetically, hydraulically, or pneumatically. In the pneumatically working embodiment the drive section works by means of a pneumatic cylinder. In the case of an electromechanical drive section, an electric motor in conjunction with a flywheel can carry out the motion of the exchange member as abruptly as possible for changing the mold jaw parts. An electromagnetic drive section can be realized by using magnets for example, and by changing their polarities such that a repulsion or attraction occurs.
Since the motion during the exchange of the mold jaw parts can not be carried out fast and abrupt without leading to collisions with the mold jaw part series that continue to run, it is advantageous, to arrange a damper or damping area preferably close to the exchange member(s) during the circulating or passing around guidance or each circulation guide, which compensates a backup area during activation of the exchange member. This damper member is particularly advantageous if a circulating or running with channel module is provided that is movable in the direction of the circulation. Preferably, the circulating or running with channel module is preloaded against the direction of circulation by means of a spring member. In the case of a change of a molding channel section, this means a chamber of the exchange member and hence of mold jaw parts for exchangeable mold jaw parts, the movable rotating channel module can be moved against the direction of circulation as part of the circulating and/or pass round guides. Afterwards, when the new chamber and thus the new mold jaw parts, i.e. the exchangeable mold jaw parts possibly with optional profile, are included in the mold jaw part series, the circulation with channel module is forced back into a base position via a spring member in order to serve again as a damper member in a future exchange.
There, the damper area or spring displacement are adjustable or are at least such that during a predetermined speed of circulation of the mold jaw parts and a predetermined and preferably changeable speed of movement of the exchange member, a backup can be brought under control.
In order to carry out a coordination of the exchange operation in relation to the circulation or pass around of the mold jaw parts, it is preferable to provide a sensor for sensing the position of at least one mold jaw part. Based on the data obtained from the sensor, the exchange member or exchange members can be activated such that one chamber is replaceable by another chamber in the continuous mold jaw part series, if the boundaries of the chamber or exchange member(s) do not collide with the mold jaw parts or are not aligned with the shock/impact positions between the mold jaw parts.
Basically, the sensor or sensors can be provided at any position of the apparatus in accordance with the invention, however, in this case a processor, such as a computer for example, needs to calculate the place of an exchange member or the places of exchange members along a rotating guide or along rotating guides.
Advantageously, the molding apparatus in accordance with the invention is provided with an exchange member having a placeholder. Such a placeholder is used in a place where an exchangeable mold jaw part or exchange mold is used in order to travel with the traveling mold jaw part series or to engage with the traveling mold jaw part series in order to maintain its place in the mold jaw part series when a normal mold jaw part is removed, so that an exchangeable mold jaw part can be used easily.
Accordingly, the placeholder can be a carrier jaw at which a molding profile section is determined and wherein the exchange member only carries out a change of the molding profile section. This means that a molding profile is determined via a latching connection or the like on the carrier jaw, which follows the mold jaw part series. Then, the mold jaw part section or the molding profile section is taken and the engagement between the placeholder or the carrier jaw and the molding profile section is removed. As soon as the molding profile section that needs to be exchanged is removed, the change member latches another optional molding profile section on to the placeholder or the carrier jaw. Instead of latching, it is of course possible to perform an insertion in guidings on the carrier jaw or to assign the changing mold or the optional molding profile section differently on the placeholder or carrier jaw.
Other types of placeholders can also be employed and as mentioned above, the placeholder has an area of overlap, which overlaps from one mold jaw part to the next mold jaw part but one. In this case, the placeholder has engagement sections, which engage with the mold jaw parts and the next mold jaw parts but one, in order to prevent in this manner that the area which becomes vacant is filled up during the removal of a mold jaw part located between one mold jaw part and the next mold jaw part but one in the mold jaw part series. This means, the area of overlap should have at least the dimensions of a mold jaw part in the direction of movement of the mold jaw part series. In this manner a mold jaw part that is to be exchanged can be substituted for by a placeholder and then an exchangeable mold jaw part with an optional profile can be placed in the position of the placeholder. As soon as the exchangeable mold jaw part is at its place of destination within the travelling mold jaw part series, the placeholder can be removed again.
Advantageously, the engagement sections are designed such that they fit to respective usually available structures on the mold jaw parts of the travelling mold jaw part series. Accordingly, the engagement sections should be provided as sprockets for example, which can engage with recesses or sprockets in travelling mold jaw parts of the mold jaw part series.
Advantageously, the last described manner of a placeholder can increase the distance between mold jaw parts, for example it could have a pneumatic cylinder or the like that works in the direction of a longitudinal extension, such that the distance between one mold jaw part and the next mold jaw part but one is slightly extended in order to have clearance during the exchange process and to make the exchange process more easy.
Advantageously, in order to make the exchange process easier, the sprocket-like engagement sections, for example, are designed such that their engagement with the sprockets of the mold jaw parts before and after the exchanged mold jaw part occurs with a shift, since during the forward drive of the engagement sections into the sprockets of the mold jaw parts and because of the incline of the sprockets, the mold jaw parts are forced apart for a small distance.
Another advantageous embodiment results when a magazine section is provided at the turning areas on one side, or if necessary on both sides, of the mold jaw part series. The magazine section travels at least temporarily with the mold jaw part series, and the exchange member is preferably provided at the magazine section in a travelling manner. The magazine section can be designed as a disk-like body, which is of the same radius as the inner radius of the mold jaw part series or the guiding section for the mold jaw part series in the turning area or return area of the mold jaw part series. Preferably, the magazine section travels synchronously. However, from time to time, if needed, such as when a mold jaw part is replaced with an optional profile mold jaw part at a certain position, the magazine section is synchronized and accordingly travels synchronously. The turning area can also be a preferred area for the arrangement of an exchange member in accordance with the invention, since there are radially extending parting gaps in the turning area between the mold jaw parts of the mold jaw part series. Furthermore, the likelihood for getting caught/hooked up in this area is small and hence a temporary or continuous synchronization is more easily realized.
Advantageously, a park-magazine section is arranged in the travelling mold jaw part series across from the magazine section. Mold jaw parts that are removed from the travelling mold jaw part series through the exchange member can be parked there until they are included again into the mold jaw part series replacing the optional profile mold jaw parts. Again, just like for the magazine section a temporary or continuous synchronization is performed. The continuous synchronization has the advantage that the exchanged mold jaw parts in the park-magazine section are always automatically at the right place in the turning area across from the optional profile mold jaw parts. The automatic positioning happens at a right time suitable for an exchange process. This is assuming that there are no deviations from the continuation of the mold jaw part series.
The inserted exchangeable molds or exchangeable mold jaw parts are advantageously designed for several variants of the procedure. For example, the molding apparatus can be designed as a corrugator for a high pressure procedure, i.e. starting from the extruder a high pressure is generated in the thermoplastic moldable plastic tube such that the plastic material is closely fitted to the mold jaw parts in the molding channel. In order to include optional profiles, for example, into the corrugated pipe that is to be produced, exchangeable mold jaw parts are exchanged for a vacuum procedure. In this case, the corrugator in accordance with the invention must have vacuum conduits at least in the area of the molding channel, so that a vacuum can be generated for the vacuum procedure between the exchangeable mold jaw parts and the plastically moldable plastic tube through the openings of the exchangeable mold jaw parts. Since corrugators for vacuum procedures are sufficiently well known, no further explanation is presented here since this knowledge belongs to a person of skill in the art.
Advantageously, recesses can be provided in the exchangeable mold jaw parts for inserting objects into the recesses. The objects have to be connected to the corrugated pipe in the molding apparatus during the molding procedure. This means, for example, that pipe brackets or similar objects can be inserted and connected with the corrugated pipe during the formation of the corrugated pipe.
It can also be advantageous to provide a heating member or a cooling member to the exchange member so that mold jaw parts or exchangeable mold jaw parts can be heated or cooled. By means of modifying the temperature of mold jaw parts or exchangeable mold jaw parts it is possible to attain special effects. For example, a plastic material can be maintained in a plastically moldable state through heated exchangeable mold jaw parts for a long period of time, in order to incorporate complicated shapes into the corrugated pipe or into a section of a corrugated pipe, a sleeve section or the like.
With respect to the magazine technique it is noted that linear working magazine or exchange members can be used but it is also possible to employ other types of magazines. For example, capstan magazines can be used having different chambers for storing exchangeable mold jaw parts or mold jaw parts. However, the respective chambers need to be able to serve as a part of the circulation guides.
The present invention is described below with respect to a preferred embodiment and is explained in further detail with respect to the appended drawings. At the same time further characteristics, advantages, and objectives in accordance with the invention are presented.